The Association Between Use of Special Supplemental Nutrition Program for Women, Infants, and Children During Pregnancy and Low Birthweight Among Non-US Born Birthing People

Background: Despite immense healthcare spending per capita, maternal and infant health outcomes remain poor compared to other developed nations. Between 2012 and 2022, the rate of infants born low birthweight (LBW), defined as birthweight less than 2,500 grams or 5 1⁄2 pounds, in the United States increased by 7%. Previous studies have found that maternal participation in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) program during pregnancy is associated with lower risk of low birthweight infants among US born individuals, however, no studies examined this association among non-US born individuals. The current study examined the association between use of WIC benefits during pregnancy and LBW infants among non-US born birthing people. Secondly, this study assessed how the association between participation in WIC during pregnancy and LBW infants varied across different racial and ethnic groups among non-US born birthing people. Methods: Data from the Pregnancy Risk Assessment Monitoring System (PRAMS) phase 8 core questionnaire between 2020-2022 was used to address the aims of this study. Participants (N=5,188 non-US born birthing people who had a recent singleton, live-birth and used Medicaid as a form of payment for the delivery) with information on exposure (WIC use during pregnancy) and outcome (LBW infant defined as birth weight less than 2,500g or 5 1⁄2 pounds) were included in the analyses. Unadjusted and adjusted (maternal age, maternal race and ethnicity, income, educational attainment, marital status, receipt of prenatal care, method of delivery, pre-pregnancy diabetes, gestational diabetes, previous preterm birth, prior pregnancies, maternal smoking, and cigarettes smoked daily during pregnancy) logistic regression models were used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CIs). We also examined the associations across race and ethnic subgroups (White, Black, Asian, Other/Multiple Race, and Hispanic) using stratified models and models with interaction terms. Results: The prevalence of pregnancies with a LBW infant was 17.9% among individuals who used WIC during pregnancy and 20.1% among non-users of WIC. In the adjusted model, the odds of LBW among non-US born birthing people who used WIC during pregnancy, compared to birthing people who were eligible but did not use WIC during pregnancy, was 10% lower (OR: 0.90; 95%CI: 0.74, 1.08; p-value = 0.27), though the difference was not statistically significant. In the race and ethnicity stratified analysis, a similar, inverse, non-statistically significant, relationship between use of WIC and having a LBW infant was observed among White, Black, Asian, Other/ Multiple Race, and Hispanic groups (ORs ranging from 0.75 to 0.98). We did not find statistically significant interactions between WIC use and Race/Ethnicity on having a LBW infant (interaction p-values> 0.05; Race= 0.80, Ethnicity = 0.72). Conclusion: We found that use of WIC benefits during pregnancy was not associated with delivering a LBW infant among non-US born birthing people overall or among subgroups defined by race and ethnicity. However, our findings suggest potential inverse relationships between WIC use and having a LBW infant. Our findings underscore the need for further epidemiological studies to examine how social and structural determinants of health including services such as WIC are associated with low birthweight outcomes among non-US born birthing people.